VList: Difference between revisions

=={{header|Applesoft BASIC}}==

<lang gwbasic> 0 DEF FN CDR(X) = V(X):Q$ = CHR$ (34)

1 FOR A = 6 TO 1 STEP - 1:A$ = STR$ (A): PRINT "CONS "A$": ";: GOSUB 10: GOSUB 50: NEXT A

2 GOSUB 30: PRINT "LENGTH: "L

3 PRINT "CDR: ";:V = FN CDR(V): GOSUB 50

4 GOSUB 30: PRINT "LENGTH: "L

5 I = 3: PRINT "ITEM "I": ";: GOSUB 20: GOSUB 90:I = 8: PRINT "ITEM "I": ";: GOSUB 20: GOSUB 90

6 END

REM CONS given A$ return V

10 N = N + 1:V(N) = V:V$(N) = A$:V = N: RETURN

REM GET ITEM given I return A

20 FOR N = 1 TO I:A = V:V = V(V): NEXT N: PRINT MID$ ("",1,0 ^ V((A = 0) * 32767));: RETURN

REM GET LENGTH OF LIST given V return L

30 A = V: FOR L = 1 TO 1E9: IF V(A) THEN A = V(A): NEXT L

40 RETURN

REM PRINT STRUCTURE given V

50 C$ = "": FOR P = V TO 0 STEP 0: IF V THEN PRINT C$;: GOSUB 70:C$ = ", ":P = V(P): NEXT P

60 PRINT : RETURN

REM PRINT ELEMENT given P

70 IF P THEN PRINT Q$V$(P)Q$;: RETURN

80 PRINT "NULL";: RETURN

REM PRINT ELEMENT WITH NEWLINE given A

90 P = A: GOSUB 70: PRINT : RETURN</lang>

{{out}}

<pre>

CONS 6: "6"

CONS 5: "5", "6"

CONS 4: "4", "5", "6"

CONS 3: "3", "4", "5", "6"

CONS 2: "2", "3", "4", "5", "6"

CONS 1: "1", "2", "3", "4", "5", "6"

LENGTH: 6

CDR: "2", "3", "4", "5", "6"

LENGTH: 5

ITEM 3: "4"

ITEM 8:

?BAD SUBSCRIPT ERROR IN 20

</pre>